While sailing with Captain Pierre Marcel, the Wonder Twins and Gleek get sucked into a whirlpool. After receiving a distress call from the Wonder Twins, the rest of the Super Friends search for the twins, only to get pulled into the whirlpool themselves. They emerge in a Wonder Land that is below the Earth's crust. The Super Friends must now search for the Wonder Twins and rescue them.

Traveling from space, three pirate ships make their way towards Earth. When Captain Sinbad and his Space Pirate crew reach Earth they start stealing treasures from South America. After receiving a message on the Justice League TroubAlert, Superman and Wonder Woman confronts Captain Sinbad and his Space Pirate crew. Captain Sinbad then hurls city buildings toward a mountain range allowing the pirates to escape the two Super Friends. The Super Friends regroup to strategize and later streak off to confront the Space Pirates. While trying to stop a Space Pirate boat, Wonder Woman gets hit with a stun laser and taken captive aboard one of the ships. Meanwhile, at the Hall of Justice, the JLA satellite monitor picked up Wonder Woman, causing Zan to convince Jana to go after her. When Zan and Jana find Wonder Woman, they get trapped by the Space Pirates and a mind-controlled Wonder Woman and are made Sinbad's slaves. Wonder Woman then sends a warning to the other Super Friends to leave the Space Pirates alone or they may never see the Wonder Twins again. Superman then disguises himself as Clark Kent to enter the Space Pirates' ship and rescue Wonder Woman and the Wonder Twins. 
NOTE: This episode and The World's Greatest Super Friends episode "Space Knights of Camelon" are the only episodes of the Super Friends series where Wonder Woman's golden lasso involves truth-compelling power.